Bicarbonate-dependent action of Bay K 8644 in the smooth muscle of the rat vas deferens.

@article{Suzuki1990BicarbonatedependentAO,
  title={Bicarbonate-dependent action of Bay K 8644 in the smooth muscle of the rat vas deferens.},
  author={Nagao Suzuki and Yasuo Gomi},
  journal={Japanese journal of pharmacology},
  year={1990},
  volume={52 3},
  pages={
          413-20
        }
}
  • N. Suzuki, Y. Gomi
  • Published 1990
  • Biology, Chemistry
  • Japanese journal of pharmacology
Effects of Bay K 8644, partial depolarization with high potassium, and nifedipine on the dose-response curves of the rat vas deferens to norepinephrine, methacholine and KCI were investigated in HEPES-buffered physiological salt solution (PSS) with or without 20 mM sodium bicarbonate. In the bicarbonate-containing PSS, Bay K 8644 at 10(-6) M enhanced the maximal contractions in response to norepinephrine, methacholine and KCI by 31.4, 103.3 and 40.1%, respectively. In the bicarbonate-free PSS… 
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References

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TLDR
The results suggested that Bay K 8644 acts primarily on the voltage-dependent Ca++ channel, presumably the same site at which other dihydropyridine derivatives (Ca antagonists) act, and that the influx of Ca++ is accelerated.
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TLDR
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TLDR
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TLDR
The results suggest that the neurogenic contractions of the circular muscle of the guinea-pig vas deferens are sympathetic in nature, but that they are not mediated solely by norepinephrine.
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